Signaling system



W. S. GORTON' v SIGNALING ssrsmzmnv Dec. .18, 1928.

' Filed Aug. 21, 1925 4 Int Q7725: 'WI/fiam 56 0mm I Patented Dec. 18,1928.

UNITED STATES I 1,695,844 PATENT oFF1cE.

EWILLIAM sfeon'ron; or Lennon, ENGLAND, nssrenon To wnsrnnn nr-ncrmocoiu- PANY, mconronarnn, on NEW. YORK, N. ,Y., a oonrona'rron on NEWYORK.

' SIGNALING sYs'rnnL',

Application filed Au ust 21, 1923. sem

4 This invention relates tothe transmissionof electric currents, andaims to provide improvements in the two-way transmission'of.

such-currents, for instance inthe two-way repeating of telephoniccurrents.

lVh'ere such repeating is desired without necessitating balancingthe'impedances of the lines connected to the repeater system to avoidsinging of the repeater systemdue to local circulationof power betweenthe repeater elements, it has heretofore been proposed to employswitching means responsive to voicecurrents ,or other transmission forconditioning the repeating means to repeat.

in the desired direction. However, in such systems the necessity" foraccomplishing the closing of aswitch contact in response to thetransmission in order to condition the repeater to transmit in thedesired direction,

tends to introduce a loss in articulation, de-

' pendent upon the time consumed in closing desired direction, or itstransmitting eiiir, ciency in such dlrectlon'is ncreased, nnme 'diatelyupon the opening of a switch contact,

the contact.

- In accordancewith the invention a voice controlled repeater or currentpath is rendered operative to repeat or transmit in the the opening ofthe contact being accomplished in response to Voice currents,- highfrequency signaling currents, or the like, and without. delay due toother'mechanical movement, and

a great gain in articulation isthereby attained, because, as recenttests of the speed of operationof relays have shown, the time requiredfor a relay to break, or open its contact, is far less than the timeconsumed in the travel of the armature to make or close acontact.

Fig. 1 of the 2 is a diagram ofthe preferred embodiment,

employing push-pull amplifiers.

Referringespecially to Fig. 1, R and R are amplifiers, preferably of thewell known electron tube type, for transmitting energy fro'm line VV toline E and from line E to line W, respectively, the tube R being coupledto line W by a transformer 1 and to line batteries 10 and 10,respectively, or the like".

Associated with tube R are two equal drawing is a circuit diagram. ofone embodiment of the invention; and Fig.

sources' of E. M. Esuchas batteries ll and 12, two equal resistances 13and 14, and tworesistances 15-andi 16 whichare also equal to: .eachother. One' -endof each of the resistances- -15 and 16 is connected tothe filament of tube R and to the negative pole of battery 11, the

shown. The other ends of resistances115 and 16 are connected to the lefthandends of re-' 'sistances-13 and- 14:,- respectively, the right handend of resistance 13 being connected to ,the'positive pole of battery 11and-the right hand e nd of resistance 14 being connected to the negativepoleof battery 12. The left hand- Associated with tube R are elements11'to 20 corresponding .to elements .11 to 20 as sociated with tube R IConnected to line W by transformer 1 is the input circuit of valve relay.T of the kind described by Captain L. B. Turner in the LondonElectrician for July 4:, and July 11,. 1919, and in British patenttoTurner, No.'

130,408, accepted A-ugustY, 1919; and the in} positive pole of battery12,'and ground, as

put circuit of a similar valve relay T is con f nected to line E by thetransformer 4. The

- term valve relay is used to designate T and Tw to distinguish theseelements from the amplifiers R and R and to avoid confusing whichcorresponds more; or less to the wave' form of the primary electromotiveforce. The term valve relay on the other hand,

is used to define an instrument wherein the secondary effect, isprodueed by', but is not these elements with the ordinary contact re--lays to be'referred to later. When a three-f electrode space dischargetube or valve is .used as an amplifier, the valve and its assonecessarilya reproduction of, orproportional to the primaryelectromotive force or current. The valve'relay T comprises athree-electrode space discharge tube or valve V, having the usualcathode, anode and grid elements. and having an anode battery Ba, a gridbattery By, an inductance I0; in its anode circuit, and an inductance I7, shunted by a capacity Cg. in its grid circuit, In and Ig beingmutually inductive. The anode llt circuit also includes the coil of acontactrethe grid battery Bg,the lead 17 being then lay OR, thearmaturet of which is adapted at ground 'potential with currentflowingto short circuit the inductance Ia. The ele- 'from'the' positive poleofbatteryll through ments V, Ba,' Bg, Ia, 19,? (lg, CR, and t corresistance 13, lead 17, armature 18, resistance respond to the similarlydesignated elements 1e, and battery 12 to the negative'pole of in theTurner patent mentioned above; and battery 11 and producing voltagedrops 1n I the corresponding, elements of valve relay 13and 1 1 equaland opposite to the voltages grid potential of tube V should beadjusted.

to thecritical value just below the value rendered inoperative totransmit by nega T are designated ,V, Ba, '13" g, Ia, I'g, of batteries11 and 12 respectively, and there Cg, CR and t, respectively. i

As explained in the Turner patent, the of the resistances 15and 16.Further, the tubes R and R are normally necessary to set up oscillationsin the circuits 'tive potentials trom batteries and 10, reof theinductances Ia and 19 due to the reac- 'spectively.

tion ofthe anode and grid circuits upon each In the operation of thesystem, when'tran-sother by mutual inductance between the re rmissionapproaches the repeater from, say

spective circuits, so that when a signal 1m hne W, it enters T and whenthe energy of, pulse 1s impressed on the grni circuitosclllathistransmlsslon exceeds a certain definite tions will be started, theamplitude of the amount the valve relay T will oscillate, thusoscillations immediately rising to a large increasing its plate currentand thereby causvalue, and being accompanied by a sudden ing relay 19 toopen contact 18. I

large increase in the mean value of the As soon as the armature 18leaves its back anode current. ,At this critical value of grid contact,battery 11 sends a current from its potential the action of the deviceis very sudpositive pole-through resistance 13 and r'eden, a verysmallrise in the grid. potential sistance 15, to its negative pole, andthiscurbeing sufiicient to produce a change from the rent causes avoltage drop in resistance 15. stationary to the oscillatory condition.-The Also, battery-12 sends a current from its increase in the mean anodecurrent operates positive pole through resistance 16 and rerelayCR,'which short circuits'the inductance sistance 14:, to its negativepole. The drop In to stop oscillations in the valve relay cir in 15renders tube R operative to repeat cuit,fand thus to restore the valverelay to transmission from line W to line E; and the condition to beagain operated in response to drop in 16 renders valve relay Tinoperasignal current; for when. the valve relay has tive so that itcannot be setinto oscillation been set into oscillation, theoscillations by the voltage which R delivers to line E. would continueeven atter the signal currents This condition persists as long as energyis which lmtlated them had ceased to flow, 1nc1dcnt upon the repeater.VVhe'nenergy 1s unless some relay restoringmeanswereemnolonger incidentupon the repeater the ployed. The oscillations set upma-y be madeoriginalor normal state of aflair's'is resumed. of any high, low orintermediate frequency, Although the relay 19 should be quick to bysuitably choosing or'adjusting the various open, it should be made slowclosing, for inreactances. The use of a high frequency is stance, byarranging it to have a weak re- ,'described for valve relay Tapproaching the repeater overline V or line cycle of operation and somaintain contact preferable since in that case the setting up of storingforce, as the example, by providing oscillations by the signal requiresno ,app'reit with only a weak restoring spring (not ciable time. Theadjustment and operation shown). This will insure that the tongue ofvalve relay T is the same as that just 23 opens before contact '18closes, so that it transmission is-still approaching the repeat-Normally, that is when no transmission is er from line W, the relay Twill repeat its E, the grid potential of tube V is maintained. 18 openas long as energy is coming in. at the critical value mentioned above bya negative potential from the grid battery By, the operation of therepeater is similar to the lead 17 being then at ground'potential theoperation just described for transmission with current flowing from thepositive pole from W to E, the valve relayT rendering of 11 throughresistance 13', lead 17., arm'atube R operative and valve relay T 1nture18, resistance 14 and battery 12 to the operative. Contact 18- should,of course,

iiegative pole of battery 11- and producing be slow closing like contact'18, for the rea- Fvol-tage drops in 13 and 14 equaland opposon Jointedout in connection with contact 18. site tothe voltages of batteries'11and 152" aking the amplifiers R and R operarespectlvely- No current thenflows through two and inoperatlve, as shown in 1,

resistance 15 orresistance 16". and there is by variation of the platecurrents sends out large impulses of energy upon the lines. Thesending'of these nolse currents out on the lines can be obviated bymaking the amnlino voltage drop in either of the resistances 15, or 16.i

' Similarly, the grid potential of tube V mentioned above byanegativepotential from and R in Fig. 2 .Which is otherwise like For transmissionfrom line E to line W is normally maintained at the critical value tiersof the push-pull type, as shown at R.,;

1 with the primary Winding of the input trans Fig. 1. Theindividualtportions of the input circuits of the'upper and lower tubesof the push-pull amplifier-.R' are associated former 1 by the upper andlower'halves, re-- spectively of the secondary Winding of the inputtransformer, so that curreht'stb be of the upper and lower tubes oftheamplifier.

I are associated with-the secondary winding of the output transformer 2by-the upper and lower halves, respectively, of the output'transfo'rmer, so that an increase in the switc h ;-=thercfo includingoperating parts plate current. of the upper tube and a do crease in theplate current of the lower tube act. cumulatively vupon the secondarywinding. The voltage across resistance 15 is preferably applied to thecommon portion 'of the input circuits of the two tubes, as shown, andtends to make the potentials of the grids of the two tubes the same insign at-jany given; 'time. Thus, when this voltage-renders the uppertube operative or inoperative it simultaneously affects the lowertube inthe same way,'and the consequent changes in the space currents of thetubes act differentially ul'aon the secondary winding ef thetransformer- 2, sothat noise currents on line E due to these changes ofspace current are, obviated. i The action of "the push-pullamplifier Rin avoiding the s'e'n-din out on line .W of noise currents, due torendering the tubes ofthat amplifier-operative -and inoperative, isshinlar to the action fierR j-ust explained for amp1i-' The inventionis-not limited to the details of the disclosure, but is capable ofvarious and widely different embodiments'within the spirit and scope ofthe appended claims.

The invention claimed is:

1. In a signaling system comprising a current transmission path and acircuit-controlling device therefor having movable operating partsofsubstantial inertia, the meth-- od of operation of said system whichcomprises ca'using said parts to so move in response to flow ofsignaling current in said path as to make the operation of said devicesubstantially independent of said inertia, and increasing thetransmittingefliciency of said path immediately upon the operation ofsaid circuit-controlling device.

2. In a repeating system comprising a repea'ting element, a controllingswitch therefor including operating elements having-materialinertia, themethod of operating said systen'rwhich comprises causing said switch torespond to signalmg CUllentSWltlllILfi negligible time after theapplication of said currents thereto, and causing a change intherepeating power of said r'epeatlng element substantially immediatelyafter the opera tion of, said switch.

3'. In a two-way repeating system comprisj" 4;"In anamplifying systemcomprising an uecritn tube amplifier and a controlling havingsubstantial inertia, the 'method of operation which compr ses causingsaid switch to open in response to signaling currents in a negligibletimea'fter the applicatlon of said f current-s thereto, and renderingsaid amplifier operative substantially immediately after the opening ofsaid switch.

path, a circuit controlling. device therefor having movableoperatingparts of material inertia, means for so moving said parts in response tosignaling currents as to substantially eliminate the eifect of saidinertia on the o eration of said device, and means responsive to theoperation of said parts for immediately increasing the transmissionciliciencyof said path.

,6. In a transmission system, a repeating element, a controlling switchtherefor includsource of signaling currents, means for causcurrents' ina negligible time after their application thereto, and means forincreasing the repeatingpower of said element in a negligible time afterthe operation of said switch. a

7 A transmission system comprising a swiich, a normally inoperativeelectron tube amplifier having a control electrode, a source ofsignaling currents, means responsive to said signaling currents foropening said switch in a negl.igible.time after the application of saidsignaling current-s thereto, and means, operative-, immediately upon theopening of said switfcl for applying to said co trol electrod n el'ectromotive force of Sue character asgte render said tube operative. QI I 8. A two-wayrepeating system comprising a circuit, two normallyinoperative elec- 5. In combination, a current transmission ingoperating partsof substantial inertia, a

. ing said switch to respond to said signaling tron tube amplifiersfor-transmitting in op- 4 posite directions respectively, in saidcircuit,

, two relays each comprising a contact, means responsive tosignalingcurrents approaching said amplifiers in one direction over said circuitfor opening said' contact associated after the application of thesignaling currents thereto, means forrendermg one of said amplifiersoperatlve to transm t 1n said one direction and rendering said otherrelayinoperative immediately -upon the opening of said other contact,means responsive to signalling currentsapproaching said amplifiers insaid other direction over said circuit for opening said other contact ina negligible time after the application of said other sig-' nalsthereto, and means for rendering said other amplifier operative totransmit in said other direction and rendering said other relayinoperative immediately upon the open ing of said contact.

9. A transmission syshm' comprising aswitch, a push-pull electron tubeamplifier,

nc-ans normally maintaining. the space eurrent of saidamplifier at zerovalue, a source of signaling currents, means responsive to saidsignaling currents for open1ng sald switch in a negligible time afterthe appli';

cation of said signaling currents thereto,

' and means. operative immediately upon the opening of said switch, forcausing space current toflow in said amplifier.

1.0. A transmission system comprising an amplifying device, means toimpress signaling currents thereon and separate meansineluding anoscillation generator also responsive to ,said signaling currents forcontrolling the transmitting efficiency of said device. 11. Anamplifying device, means to impress signaling currents thereon and meansfor controlling the transmitting efiiciency of said device, said meanscomprising an osc llator 1,695,8&4.

sponse to signaling current.

normally quiescent but oscillating in re- 18. A tWo-waysignaling systemcomprising a sending station, a unidirectional current transmitting pathfor transmitting signals from said station, an oppositely directedunidirectional current transmitting path for.

transmitting signals to said station, an means, COIHPI'ISIIIQ," anoscillator responsive to signaling current for applylng a direct eurrentpotential to one of said paths tocontrol its transmittingefliciency.

14. A source of electromotiveforce, a resistanoe connected thereacross,a second source of electromotive force, aresistance thereacross,saidsources having 'poles of opposite signs, respectively, connected'together, and a conductor including a switch,

connecting points in said resistances Which are at the same potentials,respectively, as the potentials of said opposite poles con- 'nectedtogether. s

In Witness whereof-,1 hereunto subscribe my name this seventh day ofAugust A. 1).,

WILLIAM S.r-GOR'1 ON.

